The present invention relates to a novel chemical process. More particularly, the present invention relates to a process for preparing 1,3-bis(aryloxy)-2-propanol compounds including oligomeric and polymeric compounds containing 1,3-bis(aryloxy-2-hydroxy propylene functionality. The process is well suited to the preparation of this useful class of compounds, especially the above-defined class of phenoxy resins inasmuch as the process produces little or no salt by-products. Consequently, phenoxy resins prepared by the present process are especially suited for preparation of electronic components and for use in other applications where extremely low levels of ionic contaminants are desired.
Phenoxy resins are currently prepared in large volumes, most commonly by the glycidation of a bisphenol compound, especially bisphenol A, with epichlorohydrin in alkaline solution. Neutralization of the hydrochloric acid by-product results in the generation of large amounts of salt, the disposal of which may be expensive and enviromentally unacceptable. Furthermore, small amounts of such salt by-products unavoidably contaminate the resulting phenoxy resin making it extremely difficult to prepare cast objects with high dielectric properties.
It is previously known to prepare hydroxyalkyl derivatives of phenols or thiophenols by reaction of phenolic or thiophenolic compounds with cyclic organic carbonates in the presence of certain catalysts. In U.S. Pat. Nos. 4,341,905; 4,261,922; 4,310,707 and 4,310,708, the uses of alkali metal halides, stannates and phosphonium catalysts for this process are disclosed. Additional processes for preparing hydroxyethyl derivatives of phenols by the action of ethylene carbonate include the use of acids or bases disclosed in U.S. Pat. No. 2,448,767, potassium carbonate in U.S. Pat. No. 3,283,030 and alkali metal hydrides in U.S. Pat. No. 2,987,555. In U.S. Pat. No. 2,967,892, alkali metal hydroxides are disclosed as suitable catalysts for the reaction of phenols with chloromethylethylene carbonate.